FTIR analyses of water in MX-80 bentonite compacted from high salinary salt solution systems

Madejová, Jana; Janek, M.; Komadel, Peter; Herbert, Horst-Jürgen; Moog, Helge C.

doi:10.1016/s0169-1317(01)00067-9

Cited by 184 publications

(92 citation statements)

References 29 publications

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“…1). Figure 2 shows room temperature IR spectra for sodium montmorillonite (M), HTAB-modified montmorillonite (M-HTAB) and the poly(ε--caprolactone)/organophilic montmorillonite (PCL/M-HTAB) nanocomposite; the respective bands are given in the Table. The bands characteristic of the clay were assigned according to the spectral data presented earlier [6][7][8]10] and those of PCL according to data published in [9,10]. It should be observed that the degree of hydration of the samples studied was rather low since the band at 1620-1630 cm −1 , related to the H-O-H deformation, and the bands in the range of 3350-3700 cm −1 assigned to the water contained in the interlayer space, are very weak.…”

Section: Resultsmentioning

confidence: 99%

Spectroscopic Studies of Poly(ε-Caprolactone)/Sodium Montmorillonite Nanocomposites

et al. 2005

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Polymer-layered silicate nanocomposites belong to a new class of hybrid materials consisting of organic-synthetic polymer matrix and inorganic filler--layered structure clay minerals. The paper presents the results of FTIR, NMR, and SAXS studies of poly(ε-caprolactone)/sodium montmorillonite nanocomposites. We observed a correlation between the concentration of poly(ε-caprolactone) in nanocomposite samples and structural changes both of the clay mineral and the intercalated polymer. Stiffening of the clay structure appears as a result of poly(ε-caprolactone) intercalation into a clay structure.27 Al NMR studies indicated in nanocomposites two non--equivalent sites of aluminium ions, i.e. in octahedral and tetrahedral coordination, whereas in the montmorillonite clay structure the aluminium ions are located in the interlayer space too. We found also that the temperatures of structural changes and softening process of poly(ε-caprolactone) chains in the nanocomposites depend on the concentration of poly(ε-caprolactone).

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Section: Resultsmentioning

confidence: 99%

Spectroscopic Studies of Poly(ε-Caprolactone)/Sodium Montmorillonite Nanocomposites

et al. 2005

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“…The bands observed at 918 cm −1 is corresponding to Al-OH-Al bending vibrations. A complex broad band at 1048 cm −1 is appeared due to the stretching vibrations of Si-O groups, while the bands near 525 and 468 cm −1 are due to Al-O-Si and Si-O-Si bending vibrations, respectively [27]. For Co-B/ bentonite, all bands corresponds to bentonite along with band near 680 cm −1 corresponds to B lattice vibration of Co-B is observed.…”

Section: Characterization Of Co-b/bentonitementioning

confidence: 90%

Hydrogen generation from NaBH₄ hydrolysis using Co-B/AlPO₄ and Co-B/bentonite catalysts

Manna

Roy

Pareek

et al. 2017

Catalysis, Structure & Reactivity

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Aluminium phosphate and bentonite supported Co-B catalyst were synthesized via two step impregnation-reduction method for sodium borohydride hydrolysis. The synthesized catalysts were characterized by XRD, FTIR, XPS, FE-SEM, FE-TEM, BET, ICP-AES techniques and tested for NaBH 4 hydrolysis reaction. The results demonstrated that the synthesized supported Co-B catalysts greatly facilitate the NaBH 4 hydrolysis reaction. Highest hydrolysis rate observed for Co-B/AlPO 4 and Co-B/bentonite catalysts are 6.50 and 3.91 L min −1 g −1 , respectively, with 2 wt% NaBH 4 , 5 wt% NaOH solution at 30 °C. The hydrogen generation rate was found to increase with experimental temperature. Activation energy for the hydrolysis reaction was observed to be 37 and 40.2 kJ mol −1 for Co-B/AlPO 4 and Co-B/bentonite catalysts, respectively.

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“…17 The intensity of the peak decreased on increasing the loaded amount of Cs + . It was saturated at nearly half of the initial absorbance on approximately 100% loading of Cs + ions.…”

Section: ¹1mentioning

confidence: 95%

XRD and HRTEM Evidence for Fixation of Cesium Ions in Vermiculite Clay

et al. 2012

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X-ray diffraction and high-resolution transmission electron microscopy showed that cesium ions (Cs + 's) in a vermiculite clay formed a segregated monoionic layer in the interlayer spaces. Each ion was fixed simultaneously at the centers of hexagonal rings in the upper and lower silicate tetrahedral sheets. No Cs + was eluted even when Cs + vermiculite was kept at 80°C for 48 h in the presence of a large excess of Al(NO 3 ) 3 or [Co(NH 3 ) 6 ]Cl 3 . 137 Cs is a major radioactive component of high-level nuclear wastes. After the accident in the nuclear power plants at Fukushima last March, it has been widely dispersed in the northern Kanto district of Japan and is thought to be mostly fixed in soils.1 Accordingly the removal of Cs + from soils is an urgent problem for lowering the radioactivity level in that area.As is well known, Cs + is selectively and strongly adsorbed by the phyllosilicate fraction of soils.2,3 A number of works have been reported on the interactions of Cs + with clays and its environmental fate.47 Some of the conceptual models are presented to explain the high affinity of Cs + toward clays such as a frayed edge-planar site. 810 No evidence, however, has been presented so far concerning its fixed state at an atomic scale. The understanding of the detailed structure of immobilized Cs + can be a first step to develop methods of purifying radioactively contaminated soils.We applied X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) to study the interaction of Cs + with a clay. The results gave insight for understanding its extremely high stability.As a phyllosilicate clay, magnesium vermiculite (product from Transvaal, South Africa: denoted as Mg-Verm) 11 was used (Supporting Information; SI). 21 Its physical and chemical properties have been reported elsewhere.12 Actually it is the interstratification of almost the same amount of the vermiculite layer with hydrated Mg 2+ and K + -mica layer with K + at the interlayer spaces, as shown below. This mineral was recently used as an adsorbate to remove Cs + in sea water. 13 1.0 g of MgVerm was suspended in 5.0 mL of aqueous solution containing 18, 45, or 100 mmol L ¹1 CsNO 3 (denoted as samples (I), (II), and (III), respectively). The suspensions were stirred for 48 h at room temperature. After they were filtrated off, the clay particles were dried and subjected to XRD, FT-IR, and HRTEM. The filtrates were analyzed by ICP measurements. The specimens for HRTEM were prepared according to the method described in our previous work.14 Clay samples were embedded in epoxy resin, applying pressure so that the (001) planes of the clay fragments were oriented. Then they were sliced perpendicular to the (001) planes, polished mechanically, and thinned to electron transparency by argon ion-milling. Finally the samples were carboncoated before they were examined by TEM. HRTEM observation was performed at 200 kV using a JEOL JEM-2010UHR electron microscope (Cs: 0.5 mm) with a LaB 6 filament. Table 1 shows the results of the ICP ...

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FTIR analyses of water in MX-80 bentonite compacted from high salinary salt solution systems

Cited by 184 publications

References 29 publications

Spectroscopic Studies of Poly(ε-Caprolactone)/Sodium Montmorillonite Nanocomposites

Spectroscopic Studies of Poly(ε-Caprolactone)/Sodium Montmorillonite Nanocomposites

Hydrogen generation from NaBH₄ hydrolysis using Co-B/AlPO₄ and Co-B/bentonite catalysts

XRD and HRTEM Evidence for Fixation of Cesium Ions in Vermiculite Clay

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FTIR analyses of water in MX-80 bentonite compacted from high salinary salt solution systems

Cited by 184 publications

References 29 publications

Spectroscopic Studies of Poly(ε-Caprolactone)/Sodium Montmorillonite Nanocomposites

Spectroscopic Studies of Poly(ε-Caprolactone)/Sodium Montmorillonite Nanocomposites

Hydrogen generation from NaBH4 hydrolysis using Co-B/AlPO4 and Co-B/bentonite catalysts

XRD and HRTEM Evidence for Fixation of Cesium Ions in Vermiculite Clay

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Hydrogen generation from NaBH₄ hydrolysis using Co-B/AlPO₄ and Co-B/bentonite catalysts